The housing, casing or container for a computer defines a space in which various heat-generating electronic components are secured, typically mounted on boards which themselves are secured in the housing. It is known to use heat sinks, for example conductive or phase change heat exchange components at or in thermal communication with specific components to cool the heat generating electronic components and further provide heat dispersion with one or more fans. Typically the fans move air for the purpose of heat removal from the above mentioned conductive or phase change components or in some cases directly from the electronic components. Enhanced surface designs for improved convective heat transfer are sometimes applied. Fans or blowers are also used to move or circulate air within the space of the casing to provide convection and thereby heat removal via the air without any priority regard to specific components or move air to provide airflow from and to the casing and to and from the ambient environment. In a computer system there are often a variety of different heat-generating components including high power density microprocessors some, if not many, having different cooling requirements. Cooling of the most important electronic components is not necessarily achieved by providing maximum cooling air speed over all components which can increase the air temperature unnecessarily from cooling non-critical components capable of operating reliably at elevated temperatures or operating at lower energy densities not leading to a critical operating temperature before such air actually reaches the more critical component, and whereby the now higher air temperature makes it more difficult to provide effective cooling to the critical component.
Methods and components for achieving improved cooling and thermal management of electronic components are called for as faster processing speeds require higher power levels for electronics and where higher resolutions require higher power levels for displays, both leading to higher heat loads, which need to be removed in order to maintain operating temperatures of the components below critical temperatures at which the reliability and ultimately the functionality is compromised. Moreover, computing, display, recognition, targeting and other electronics systems may need to be operated in non-air conditioned spaces, such as tents, the back of vehicles, inside non-air conditioned trucks and military fighting vehicles or outside under high ambient temperature conditions much harsher on the thermal management of the electronic components as compared to conditions encountered in air conditioned office spaces, typically maintained at or below about 75° F. Ambient temperatures in the above mentioned non-air conditioned spaces can reach temperatures well above 100° F. often even above 120° F. For such operating scenarios improved methods and apparatus for cooling electronics is required even if the electronic components are not at the high end of the heat generation spectrum. Electronic equipment designed to operate in harsh environments sometimes requires the housing or portions of the housing to be isolated from the ambient air to avoid contamination of the electronic components and boards with dust, dirt or moisture of the environment. In such cases the housing or a portion of the housing is sealed and the necessary heat transfer required to manage the temperature of the heat generating electronic components is further limited in that it must be accomplished with means providing heat transfer through the housing walls, often inadequate because the surface area and thermal conductivity of the housing wall is usually incapable of transferring a significant portion of the heat to be rejected, nor is the housing wall commonly in good thermal contact with the heat generating components.